Electrical measuring instrument.



A. B. REYNDBRS.

ELECTRICAL MEASURING INSTRUMENT.

APPLICATION FILED SEPT. 8, 1910.

Patented Dec. 15, 1914.

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Sdlelf l ES B. EEYNDERS, @F WILKENSBUIRG, PENNSYLVANIiQi, ASSIGNGE, T WESTING- I-IUUSE ELECTRIC AND MANUFACTURING CQItZPANZ, A CORPORATZODT OF PENlT- SYLVANEA.

ELEGTRICALTEEASURZNG "INSTRUMENT.

Specification of Letters Patent.

A L Patented wee. no,

Application filed September 6, 1910. Serial No. %,764.

To aZZ whom it ma concern:

Allegheny and State of Pennsylvania, have invented a new and useful improvement in Electrical Measuring'lnstruments, of which the following is a specification.

My invention relates to electrical measuring instruments of the electrostatic type, and it has particular reference to such instruments as are adapted for use in measuring very high potentials.

The object of my invention-isto provide a device of the above-indicated class that shall be of particularly simple and durable construction and shall embody adequate means for adapting the instrument "for accurate use over a Wide range of voltages.

ldleretofore, it has been common practice to employ auxiliary condensers in combination with oil-immersed electrostatic instruments, and to provide means whereby the capacity of such condensers could be va ried, in order to efi'ect a change in the range or" operation. of the instruments. However, in such devices, considerable dificulty has been experienced in suitably mounting and insulating said units from the metallic recept'acles to which they were secured.

According to my invention, I employ a bushing of the so-called condenser ty' e for insulating the high-voltage terminal trom the inclosing casing, and 1 connect the instrument vanes in multiple with one or more layers or said condenser bushin and also make use of a plurality of said layers as an auxiliary condenser. Another simple condenser unit that is utilized comprises one of the stationary vanes and the adjacent casing. In order to adapt said instrument for different voltage ranges, suitable means are employed to short-circuit either or both of said condenser units, as necessitated by the voltage to be measured. llt is obvious that, by thus taking advantage of the existing properties of the several component elements, an instrument of exceptional simplicity, compactnem and durability is obtained.

in the accompanying drawing, Figure l is a view, partially in vertical section Y the movable vane 5 from its normal partially in elevation, of an instrument constructed in accordance with my invention. Fig. 2 is a diagrammatic view of the circuit connections of the instrument shown in 1, and Fig. 3 is a view, partially in vertical section and partially in elevation, of a portion of the condenser bushing shown in Referring to the detail, on electrical measuring instrument 1 cornprises a metallic receptacle or tank 2 containing'a suitable insulating liquid 3 and connected to ground at G, a cover plate l for said receptacle, mov e 5 a "c urality of stationary vanes o and a in electrostatic relation to the vane 5, an indicating mechanism 8, a condenser bushing 9, a plurality of con-(l as its and 11, and suitable cans l2 (i for shortcircuiting the condenser Lilli mow able vane 5 comprises a pair of hollow cylindrical bodies 14- and 15, and a connecting member 16. The movable vane 5 is pivotally suspended from the cover plate by means oi the indicating r in a yoke member and an insulating rod 18.

The indicating mechanism 8 comprises a bracket member 19, which is suitably secured to the cover plate 4 and is adapted to support a spindle 2O bete upper and lowerbearings 2i and 22, respectively. A pointer or indicator 23 projects laterally from the spindle and cooperates with plurality of ditlerently calibrated scales 24:, 25 and 26 upon the u per side of the cover plate 4-, to indicate, y its angular deflections, the forces measured by the instrument. The spindle 20 is s cunded by spiral spring 2?, the opposc ends of which are connected, respectively, to said spindle and to the bracket member 19, rotation of position being opposed by the tension thereoi'.

The station-ar vanes 6 '3 are c drically curved and are so arranged that their concave surfaces oppose each and are in close proximity to the cylindrical bodies 14: and 15. The stationary vane is suspended from the cover by means of insulating rods 28 and 29, while stationary vane 7 is mounted upon the terminal bushing 9 and in electrical contact with one disposed of its conducting layers by means of a supporting member 30. One end of said supporting member 30'is' attached to said stationary vane and its other end is provided with two arms 3:2, which are adapted to surround said bushing and to be securely clamped thereto by means of a screw 33.

The member 30 is also provided with an opening 31 for a purpose to be hereinafter explained. The vanes 6 and 7 are so disposed with respect to the movable vane 5 that, as the latter is deflected from its normal or zero position, the distances between the bodies 1-l and 15 and the vanes 6 and 7 decrease at such arate that the scales 24, 25 and 26 may be uniformly sub-divided.

The condenser bushing 9, which issurrounded by a metallic sleeve 3;, extends through a suitable opening 35 in the cover plate 4 and is secured in position by means of bolts 36. The bushing 9 is of the wellknown condenser type of construction and comprises a metallic tube 37, about.

which are wound alternate layers of insulatin material 38 and conducting -material 39. he innermost layers are relatively long and the outer layers are relatively short, so that a stepped structure is provided, in which the extremities of adjacent conducting layers are separated by considerable lengths of insulation.

The upper end 40 of the tube-37 constitutes the external terminal of the instrument from which a coil spring 41 is suscondenser bu shin pended within the tube by means of a conducting wire 42. A metallic sphere 43 is similarly suspended by a conducte ing wire 44 from lower end 45 of said spring. An'insulating cord 46 is suitably secured to the sphere 43 and extends through the opening 31 in the'supporting member 30 and through an opening 47 in the cover plate 4. The extremity of said cord is provided with a knob or button 48 which normally rests upon the top of the cover 4 and may be utilized to pull the sphere 43 into contact with the supporting member 30 against the action of spring 45. The condenser unit 11 comprises a plurality of sections 49 which constitute parts of 9, and condenser unit 10 embodies the stationary vane 6, the adjacent grounded casing 50 and the interposed, insulating liquid.

In order to bridge across condenser unit 16 a sphere 51 is attached to the grounded casing 50 by means of a flexible conducting connection 52, and is also rovided with an insulating cord 53 which extends up through insulating rod 28 and is attached to a. button 5% which normally rests upon the cover 4-. Barriers 55 and 56 are interposed between the condenser bushing 9 and the adjacent side and bottom walls, respectively, oi the receptacle 2, in order to pre- -fore evident that, if stationary vane 7 is connected to a conducting layer 57, the voltage impressed upon said vane is equal to the total potential of the circuit minus the drop in potential over the layers d9 which intervene between the supporting member 30 and the tube 37.

Referring more particularly to Fig. 2, it will be noted that the stationary vanes 6 and 7 are connected inparallel to a plurality of layers which exist between the layer 57 and the grounded sleeve 34. Therefore, the drop of potential over said sec-" tions is,- in reality, what is measured by the instrument, and it is evident that,.by properly designing and arranging the stationary and movable vanes, said vanes may be adapted to be connected in parallel to any desired number of layers which compose the condenser bushing. However, those; skilled in the art will readily understand that the operation of the instrument is not afiected if the ground connection 58' is re moved so long as the sleeve 34 is at the isame potential as the receptacle 50 and, in such case, condensers .10 and. 11 and the stationary and movable vanes may be regarded as connected in series between the source of line potential and the ground. If, as shown on the drawings, the condensers 10 and 11 are actually in circuit, the instrument is adapted to the measurement of the highest voltages of which it is capable, and the voltage which exists between stationary vanes 6 and 7 will be equal to the potential of the circuit minus the sum of the drops in potential across the condensers l0 and 11. The voltage corresponding to the actuating force will, therefore, be indicated upon the scale 24. If it is desired to adapt said measuring instrument for a range of voltages lower than can be accurately indicated "upon scale 24, the plurality of layers which constitutecondcnser 11 may be short-circuit ed, by pulling the sphere 43 upwardly into contact with the supporting member 30, by'means of the cord 46 and the button 48. Under these conditions, the voltage which exists between stationary vanes 6 and 7 is equal to the difference between the terminal-"voltage and the potential drop across condenser 10, the direct volt-age reading being indicated upon scale 25. If a still lower range of readings is desired, condenser 10'may be shortcircuited by sphere 51 which is drawn into engagement with stationary vane 6 by means of the cord 53 and the button 54. it

1 and connected in areaeco my invention, and l desire that only such.

limitations shall be imposed as are indicated in the appended claims.

l claim as my invention:

1. An electrical measuring instrument comprising a receptacle containing insulating liquid, a condenser bushing composed of alternate layers of insulating and conducting materials, and adapted to extend through an openin in said receptacle and to. separate the source of potential from said receptacle, a movable member and stationary vanes arranged in electrostatic relation arallel to one or more layers of said bushin 2. An instrument adapted for a plurality of ranges of measurement and comprising a receptacle containing insulating liquid, tw

stationary vanes and a movable member supported in electrostatic relation thereto, a condenser bushing composed of alternate layers'of insulating and conducting materials, one of said stationary vanes losing electrically connected to an intermediate conducting layer of said bushi r and the second stationary vane, the receptacle and the intermediate liquid constituting a condenser unit, means for short-circuiting said condenser unit, and a separate means for short-circuiting the plurality of layers between said intermediate layerand the source of potential. q

3. An electrical measuring instrument comprising a receptacle, a condenser buslr' 111g composed of alternate layers of insulating and conducting materials, stationary vanes and a movable member supported in electrostatic relation thereto, and a condenser unit, said condenser unit and said stationary and movable vanes being connectcd in series with each other and in multiple to one or more layers of said condenser bushing.

4. An instrument comprising a receptacle containing insulating h uid, a condenser bushing composed of a ternate layers of insulating and conducting materials, stationary vanes and a movable member sup ported in electrostatic relation thereto, one of said vanes having a connection to a conducting layer of said bushing.

5. An electrical measuring instrument comprisin a receptacle containing insulating liqui stationary and movable vane members disposed in-electrostatic relation, and a condenser bushing composed of alternate layers of insulating and oonductmg materials for insulating the high potential conductor from said receptacle, one stationary vane member being mounted upon the condenser bushing and in electrical contact with a conducting layer thereof.

6. An electrical measuring instrument comprising a receptacle containing insulating liquid, stationary and movable vane members arranged in electrostatic relation, and a condenser bushing composed of alternate layers of insulating and conducting materials for introducing the high potential to bemeasured through the receptacle, said stationary and movable vanes being connected in series with a plurality of layers or said bushing, between. the source of potential and the rece tools.

7. The combination with an instrument comprising a receptacle containing insulating liquid, stationary vanes and a movable member supported in electrostatic'rclation, of a condenser bushing composed of alternate layers of insulating and conducting ma; terials, one of said stationary vanes being secured to said bushing and in electrical contact with one of its conducting layers; a coiled spring suspended within said bushing, a conducting body suspended from said spring at the lower extremity of said bushing, and means for causing said body to make contact with the stationary vane which is associated with said bushing.

8. An electrical measuring instrument comprising a receptacle, containing a body of insulating liquid, a bushing composed of alternate layers of insulating and conducting materials, a movable member and two stationary vanes disposed in electrostatic relation,-one of said stationary vanes being suitably suspended and insulated from the cover and in proximity to a side wall of said receptacle and the other being held in position by a supporting member which is clamped to said condenser bushing and in electrical contact with one of its conducting layers.

9. An electrical measuring instrument adapted for a plurality of ranges of measurement, and comprising a receptacle containing a body of insulating liquid, a condenser bushing composed of alternate layers of insulating and conducting materials, stationary vanes and a movable member sup ported in electrostatic relation, one or both of said stationary vanes cooperating with the liquid and ad acent metal parts to form condensers, and separate means comprising yieldingly suspended conducting bodies and members of insulating material attached thereto for short-circuiting said condensers.

10. The combination with bushing composed of alternate and concentric layers of ltlil insulating and conducting material forming a condenser unit, of an electrostatic indicating device associated with said bushing having a portion thereof supported thereby and electrically connected to one of its conductin layers.

11. he combination with a bushing comprising alternate and concentric layers of conducting and insulating material constitutinga condenser unit, of an indicating instrument electrically connected to one of said conducting layers and means for supporting a portion :of the said indicating instrument from one of said conducting layers.

The combination with a bushing, comprislng: alternate and concentric layers of insulating and conducting material, of an indicating 'device connected in parallel to masses" In testimony whereof, I have hereunto.

subscribed my name this 18th day of August, 1910.

ARTHUR B. REYNDERS. Witnesses:

C. W. MCGHEE, R. J. Dnannonn. 

